Railbed

ABSTRACT

A railbed comprises a supporting element in the form of a sleeper, plate or the like of a cast compound such as concrete and an insert preferably of electrically insulating material which is grouted or embedded therein.

United States Patent 1191 Thim et al. Sept. 9, 1975 [54] RAILBEI) 3,369,753 2/1968 Olson 238/283 3,544,006 12/1970 Penning 238/283 [751 Inventors: Helge Gunna' Th'm, 3,598,312 8 1971 Hamilton, Jr... 238/84 flelgevarma; Lamar! Bowl), 3,662,952 5 1972 Berks et al 238/281 Bromma, both of Sweden [73] Assignee: A-Betong AB, Vaxjo, Sweden Primary ExaminerM. Henson Wood, Jr. [22] Ffled' May 1974 Assistant Examiner-Richard A. Bertsch [21] A 1 N 463,103 Attorney, Agent, or FirmSughrue, Rothwell, Mion,

Zinn and Macpeak [30] Foreign Application Priority Data May ll, 1973 Sweden 7306727 52 us. 01. 238/84; 2.38/2; 238/283; [57] ABSTRACT 238/265 51 Int. c1. E01B 3/00 A railbed Comprises a Supporting element in the form 58 Field of Search 238/283, 281, 282, 83, of a Sleeper, p or the like of a cast Compound such 238/84, 29, 30, 2, 91, 264, 265, as concrete and an insert preferably of electrically in- 23 /270 2 7 304 sulating material which is grouted or embedded therein. [56] References Cited UNITED STATES PATENTS 8 Claims, 4 Drawing Figures 1,151,891 8/l9l5 McGonigal 238/283 PATENTEU SEP 9 I975 l l 1 I I I IJ Fig. 3

RAILBED BACKGROUND OF THE INVENTION 1. Field of the Invention v This invention relates to railbeds of the kind comprising a supporting element in the form of a sleeper, plate or the like of a hardened cast compound such as concrete.

2. Description of the Prior Art A modern track built up in accordance with the classical track construction pattern consists of three main parts: sleepers or ties, rails and a fastening or fastening system which serves to unite these into a unit, ie the track. The fastening must be able to absorb and distribute the load exerted on a track while at the same time it must give the rail an elastic attachment and to some extent dampen the oscillations caused by the traffic.

A modern track is often divided into sections which are electrically insulated in their ends and form socalled track lines by means of which signals of different kinds are controlled. This, in turn, necessitates the two rails being electrically insulated from each other. A suitable and common way of achieving this is to build in electrical insulation in the fastening. For this purpose, use is frequently made of a loose elastic insert in the form of a separate element manufactured of a material with sufficient electrical insulating properties.

Often also included in a modern rail fastening are spring parts of steel which in an appropriate manner are attached to corresponding fixed parts in the sleeper and which impart retaining properties to the fastening, elastic inserts in the form of separate elements which give the rail a double elastic attachment while forming at the same time a part of the electrical de-insulation of the rail, and special insulation inserts which serve to achieve complete insulation of the rail and which can be located between the spring part and the rail foot.

In a ballastless track, the construction can make it necessary to provide more or less continuous elastic inserts for the support and fixing of the rails and with the same demands on electrical insulation, etc., as specified above for the classical track construction. The surface usually obtained does not provide the most ideal contact surface for such an elastic insert. In such cases, irregularities in the surface which reduce the service life of the insert must always be allowed for.

A modern fastening often consists of many separate parts, which necessitates a considerable amount of manual work when a track is being assembled or disassembled. This is a decided disadvantage, particularly as a large number of included parts makes mechanization of the work difficult. Each individual component part of a fastening system, moreover, with its deviations from the correct dimensions, contributes towards the inaccuracy of a vital final dimension. The greater the number of parts included in the fastening system is, the more difficult it becomes to achieve the wanted dimensional accuracy.

The following publications describe previously known railbeds illustrative of the state of the art. Each one thereof suffer from one or more of the abovementioned drawbacks:

Swedish patent 209,032 issued on June 30, 1966 Swiss 520,233 Mar. 15, 1972 Swedish lay-open-print 321,494 published on Mar. 9,

SUMMARY OF THE INVENTION can be so structured that, at the same time, it accomplishes sealing of the mould and a support for parts embedded in the element. The side of the insert facing towards the concrete can be so configured as to be anchored to the desired extent in the concrete in the course of casting and be held thereto upon removal from themould. On the side facing towards the rail the element can additionally be so designed that when the complete track is assembled it satisfies the abovementioned requirement which from the standpoint of track construction can be demanded of an elastic insert.

In all known methods for manufacture of concrete sleepers the elastic insert can be accurately fixed in the mould, which ensures a final product with substantially improved dimensional accuracy. Also when other types of supporting elements are involved, grouting or embedding of an elastic insert can easily be carried out.

The grouted or embedded insert can, if desired, be so structured that it contributes towards ensuring good and proper positioning of embedding parts for fastening. Effective sealing between the embedding parts concerned and the concrete mould can then easily be obtained.

The invention also allows modern factory-scale manufacturing of a railbed with the greater dimensional accuracy then obtainable, at the same time as the work on tracks is simplified in that several manual work operations can be dispensed with. Moreover, remaining track work can more easily be mechanized. Similar advantages-.are also obtained during subsequent track work, for instance stress equalization, rail replacements, etc.

i The embedded elastic insert can be so designed or combined with other elements that it partly or wholly ensures retention in place of the rail.

In order to ensure a practicable joint between sleeper and insert the insert can be provided with anchorages in the form of pins, ribs, strips or the like. These, in turn, can be so configured that in addition to the anchoring effect they also give the plate wanted variable elastic properties.

BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the invention will be described in greater detail in the following description, wherein reference is made to the accompanying schematic drawing.

FIG. 1 shows a part of a mould for manufacturing a railbed according to the invention provided with an embedded elastic insert.

FIG. 2 is a section along line 22 in FIG. 1.

FIG. 3 shows an example of a track construction which incorporates a railbed according to the invention.

FIG. 4, finally, shows a part of a track construction in which the elastic insert contributes towards retention of the rail.

DESCRIPTION OF PREFERRED EMBODIMENT Illustrated in FIG. 1 is the manufacture of a railbed according to the present invention provided with a known rail fastening. Manufactured in a mould 2 is a sleeper 1, embedding parts 3 for the rail fastening being shown schematically in broken lines. Placed in a fixture 4 for the fastening parts which are to be embedded or grouted in the sleeper is an elastic insert in the form of a plate 5. The said plate 5 can be made of rubber or plastic of a suitable quality. The main purpose of the plate is to impart the wanted elastic properties to the rail mounted in the fastening in the finally assembled track. The plate 5 can, thus, be so formed that desirable elastic properties for occurring horizontal and vertical forces are obtained in view of the actual frequencies of the spectrum of forces.

In order for the plate 5 also to contribute towards good fixing of the embedding parts it is provided on two sides with an elongation 5a, so that it connects in a suitable manner the corresponding embedding part 3 and helps to improve the dimensional accuracy.

For the rest the plate is given such a shape that it fits well into the mould 2 and also effectively seals the recesses or core-outs in the mould. Shown at section 22 is a method of affording a seal against a mould surface 2 by means of a suitable formed strip 512. By means of effective sealing, cement sludge can be prevented from being displaced out of the concrete form during castmg.

In order to obtain sufficient anchoring of the plate 5 in the mould during the actual casting operation the plate in the example shown has been provided with four small anchoring hooks 5c, so dimensioned that they easily loosen from their position in the mould when the finished concrete sleeper is being removed from the mould. The plate 5 embedded in the sleeper must nevertheless be sufficiently anchored and fixed in the sleeper 1. To achieve this, the plate has been provided with a plurality of anchoring pins. The holes in the concrete formed by these pins can subsequently serve as guides and fixings for a replacement plate if, in the finished track, it is found necessary to change the embedded plate on account of, for example, mechanical wear.

Shown in FIG. 3 is a track construction comprising a rail 8 carried on a railbed. The bed consists of a concrete sleeper 1, embedded in which is an elastic plate 5, provided with upwarddirected side edges so that it encases the foot part of the rail. The plate Sis anchored in the concrete by means of longitudinal strips 5e.

The rail is retained on the bed by means of a conventional spring 9. Shown in FIG. 3 also is part of a wheel 10 carried by the rail 8.

FIG. 4 illustrates a part of a track construction with a railbed according to the invention, in which an elastic plate 5 embedded in a sleeper 1 has been provided with a hook-shaped projection 5d, which partly encase the foot part of the rail, so that the elastic plate contributes towards retention of the rail. The retaining effect is strenthened by a spring 9 shaped correspondingly to the hook-shaped projection 5d.

What is claimed is:

l. A railbed, comprising:

a. an elongated sleeper member formed of hardened cast concrete and adapted to serve as a rail supporting element,

b. an insert of elastic material integral with the sleeper member and imbedded therein during the casting thereof, said insert being adapted to serve as a cushioning mounting pad for a rail secured to the sleeper member, and

c. anchoring means attached to the insert and extending into the sleeper member for securely fastening the insert thereto in a predetermined position.

2. A railbed according to claim 1, wherein the insert consists of a plate of electrically insulating material.

3. A railbed according to claim 1, wherein the insert is provided with recesses, core-outs and thickened sections to define a geometric shape that gives the insert variable elastic properties.

4. A railbed according to claim 1, wherein rail fastening parts are groutedin the sleeper member, and the insert is adapted to serve as a seal around said fastening parts.

5. A railbed according to claim 1, wherein the insert is provided with side supports for the rail.

6. A railbed according to claim 1, wherein the insert has positioning projections that engage recesses in a casting mold, whereby the insert adopts and remains in a predetermined position in the mould during the casting of the sleeper member.

7. A railbed as defined in claim 1 wherein the anchoring means are pins.

8. A railbed as defined in claim 1 wherein the anchoring means are elongated ribs. 

1. A railbed, comprising: a. an elongated sleeper member formed of hardened cast concrete and adapted to serve as a rail supporting element, b. an insert of elastic material integral with the sleeper member and imbedded therein during the casting thereof, said insert being adapted to serve as a cushioning mounting pad for a rail secured to the sleeper member, and c. anchoring means attached to the insert and extending into the sleeper member for securely fastening the insert thereto in a predetermined position.
 2. A railbed according to claim 1, wherein the insert consists of a plate of electrically insulating material.
 3. A railbed according to claim 1, wherein the insert is provided with recesses, core-outs and thickened sections to define a geometric shape that gives the insert variable elastic properties.
 4. A railbed according to claim 1, wherein rail fastening parts are grouted in the sleeper member, and the insert is adapted to serve as a seal around said fastening parts.
 5. A railbed according to claim 1, wherein the insert is provided with side supports for the rail.
 6. A railbed according to claim 1, wherein the insert has positioning projections that engage recesses in a casting mold, whereby the insert adopts and remains in a predetermined position in the mould during the casting of the sleeper member.
 7. A railbed as defined in claim 1 wherein the anchoring means are pins.
 8. A railbed as defined in claim 1 wherein the anchoring meanS are elongated ribs. 